Composition for cadmium plating baths



Patented July 28, 1931 UNITED STATES PATENT OFFICE,

CHAD E. HUMPHRIES, OI INDIANAPOLIS, INDIANA, ASSIGNOB I.'O JAMES C. IAT'IEN, OF

. INDIANAPQLIS, INDIANA comrosrrrou I'QB' cranium rm'rme Barns NoDrawing.

In electrodepositing cadmium on the sur-. face of metallic or other objects for the purpose of rustproofing the same or otherwise improving the surface thereof, a satisfactory and efiicient bath consists essentially of an aqueous solution of cadmium sulphate either prepared from the oxide or in any other suitable manner, a certain quantity of free sulphuric acid and a briglhtening agent such as a glucoside, to whic may be added a certain amount of ammonium sulphate. By means of a bath of this character I have been enabled to obtain excellent deposits'of metallic cadmium, which are in every way. suitable for practical purposes.

The solution must, of course, be made up in a plating tank such as are used in plating shops. The object of the present invention is an improvement or modification of the ingredients or chemicals which are used to make up the above-mentioned acid plating solution so that the same can be packed in a dry form for shipment to electroplaters, in such a manner that the material is supplied to the trade in suitable containers and is ready for immediate use, or canbe conveniently stored, if required. When dissolved in water a mixture of this character will give a ca will have in general the characteristicsof the above-mentioned bath, and will be maintained and will function in the same manner.

The glucosidey which is one of the ingredients of the above-mentioned bath, serves the purpose of a brightening agent, as

' it improves the quality of the deposit.

Inasmuch as the cadmium salt which undergoes electrolysis in the above-mentioned bath is cadmium sul hate, I may'supply the same in the form oi a cadmium compound which when the mixture is dissolved in water, will form the said sulphate with'the help of the ingredient or ingredients containing the S0 radical. Thus for instance I may use cadmium oxide, cadmium hyium plating bath, which Application filed September 23, 1927. Serial'ITo. 221,619.

droxi'de, cadmium carbonate, cadmium sulphate or chloride or any other cadmium-saltv which may be found suitable.

I have found the following composition of matter suitable for the purpose indicated:

2% to 3 oz. cadmium oxide 6 oz. acid sodium sulphate 4 02. ammonium sul hate 1 to 10 grams glucoside A satisfactory glucoside is a cane sugar caramel.

For the cadmium oxide in the above formula therem quantities of cadmium carbonate. The

above uantity is a unit amount to be dissolved in one gallon of water.

The above materials can be mixed dry in a mixi machine and packed in metal containers aving .a resined lining.

I Another formula which I have found suitable for my purpose is as follows:

4 oz. cadmium sulphate 6 oz. ammonium sul hate I 1 to 10 grams glucoside Cadmium chloride may be substituted forsulphate and a brightening agent.

2 A compositionof matter adapted for use in forming an acid solution for the electrodeposition of cadmium, consisting of adry mixture, comprising cadmium oxide, acid sodium sulphate, ammonium sulphate and a brightening agent.

3. A composition of matter adapted for use in forming an acid solution for the elecay be substituted the equivalent ma aise trodeposition of cadmium consisting of a dry mixture, comprising cadmium oxide, 1 acid sodium sulphate, ammonium sulphate and a glucoside. 4. A composition of matter adapted for 5 use in forming an acid solution for the electrodeposition of cadmium, consisting of a dry mixture, comprising 2 to 3 oz. cadmium oxide, 6 oz. acid sodium sulphate, 4 m oz. ammonium sulphate and 1 to 10 grams of a glucoside.

5. A compositionof matter adapted for use in forming an acid solution for the electrodeposition' of cadmium consisting of 55 a dry mixture, comprising cadmium oxide, acid sodium sulphate, ammonium sulphate and cone sugar caramel. 6. A composition of matter adapted for use in forming an acid solution for the 20 electrodeposition of cadmium, consisting of a dry mixture, comprising-2V to 3 oz. cadmium oxide, 6 oz. acid' sodium sulphate, 4 oz. ammonium sulphate and 1 to 10 grams of cane sugar carame. i

25 7., A'composition of matter adapted for use in forming an acid solution for the electrodeposition of cadmium, consisting of a dry mixture, comprising cadmium sulphate, ammonium sulphate and cane sugar go caramel. I

- In witness whereof, I, H. HUM- rHBms, have hereunto set my hand at Indianapolis, Indiana, this 28th day of June, A. D. one thousand nine hundred and at twenty-seven.

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